title: A pilot evaluation of a brief non-verbal executive function assessment in Parkinson's disease.
abstract: OBJECTIVE
  Screening for cognitive impairment in the clinical or community setting is often hampered by the lack of a suitable assessment that is not overburdened with complex administration and scoring methods. We have developed non-verbal cognitive screening instrument: the Weigl Token Test (WTT) from two existing instruments, the Weigl's Colour-Form Sorting Test (WCFST) and the Token Test. The aim of this investigation is to compare the modified WTT with a battery of 'Gold Standard' cognitive assessments, to determine its utility, sensitivity and specificity as a brief cognitive screen in a cohort of Parkinson's disease (PD) patients.
  
  
  METHODS
  A total of 50 PD patients consented to participate in this investigation. All participants were assessed with a battery of cognitive screening instruments including the WCFST, Mini Mental Status Examination, Addenbrooke's Cognitive Examination--Revised and Delis Kaplan Executive Function Systems. The sensitivity and specificity of the WTT to detect cognitive impairment were based upon psychiatric interview, neuropsychological assessment and application of DSM-IV criteria.
  
  
  RESULTS
  The optimal cut-point of the WTT was 116/120, and its sensitivity and specificity to detect cognitive impairment were 88% and 89%, respectively. The diagnostic accuracy of the WTT as calculated by the area under the receiver operating curve was 0.83 (95% CI 0.76-0.95), suggesting that this instrument has acceptable psychometric properties to discriminate between case and non-cases of cognitive impairment.
  
  
  CONCLUSIONS
  The WTT demonstrated excellent concurrent validity with existing 'Gold Standard' assessments of cognitive impairment. We believe that this instrument will prove to be a valuable additional screening assessment in epidemiological, primary care, specialist mental health or clinical investigations.
authors.affiliation: Academic Unit, Cardiff University, Rhyl, Denbighshire, UK.
authors.forename: Peter James
authors.initials: PJ
authors.lastname: Hobson
authors.forename: Robert Jolyon
authors.initials: RJ
authors.lastname: Meara
authors.forename: Rachel
authors.initials: R
authors.lastname: Evans
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000175:diagnosis; D056344:Executive Function / Q000502:physiology*; D005260:Female; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests / Q000592:standards*; D010300:Parkinson Disease / Q000175:diagnosis* / Q000523:psychology; D010865:Pilot Projects; D011594:Psychometrics / Q000379:methods*; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Parkinson's disease; assessment; cognitive impairment; executive function